On Aug.18, Ally Pregulman, a 25-year-old Adams Morgan resident, was biking over to a friend\'s house to make him dinner. At the time, she wasn\'t aware that she \'rider number 5 million.\' (Getty Images)

WASHINGTON — Maybe the buses and Metro trains in D.C. would be a little more crowded if not for those red and yellow bikes with the fat tires.